The disclosure of Japanese Patent Application No. 11-304316 filed on Oct. 26, 1999 including the specification, drawings and abstract is incorporated herein by reference in its entirety.
1. Field of the Invention
The invention relates to a moving object detecting apparatus, an abnormality alarm apparatus, and a load-carrying compartment opening control apparatus.
2. Description of Related Art
Many vehicles have, in addition to a passenger compartment, a trunk compartment (load-carrying compartment) isolated from the passenger compartment. The trunk compartment is provided for placing various kinds of baggage. Although it is recommended that a driver check the inside of the trunk compartment, it is an object of the invention to provide some detection or alarm for telling a driver in case of, for example, an accident where a child or a pet is locked inside the trunk compartment while playing.
Various vehicular theft deterrent apparatus have been proposed. For example, Japanese Patent Application Laid-Open No. 6-52449 discloses an apparatus that continually transmits and receives ultrasonic waves using an ultrasonic transmitter-receiver, and detects an invader based on the Doppler effect in the reflected waves from the invader. Various apparatus also exist with regard to systems that detect an invader based on detection of an interruption of an infrared ray.
If an apparatus as described above is installed in a trunk compartment, it becomes possible to detect a child, a pet, etc., confined in the trunk compartment.
However, the apparatus using the Doppler effect have problems of a complicated system construction and a high cost. Furthermore, a plurality of objects cannot be detected unless Doppler effects are detected after reflected waves from the objects are separated in accordance with the distances of the objects. However, it is difficult to distinguish a plurality of objects and detect a movement of one of the objects.
The apparatus using infrared rays also have the following problem. That is, if a piece of baggage or the like is placed near an infrared light emitter portion, no other object can be detected at all.
Accordingly, it is an object of the invention to provide a moving object detecting apparatus, an abnormality alarm apparatus, and a load-carrying compartment opening control apparatus each capable of reliably detecting a moving object while employing a simple apparatus construction.
A moving object detecting apparatus in accordance with one aspect of the invention includes an oscillator circuit that is connected to at least one electrically conductive member and that changes an oscillating frequency based on a change in capacitance of a space near the at least one electrically conductive member, and a frequency change detection circuit that detects a change in the oscillating frequency of the oscillator circuit. Based on a result of detection by the frequency detection circuit, a moving object present in the space near the at least one electrically conductive member can be detected.
If a moving object, such as a human, a pet, etc., exists near an electrically conductive member, the capacitance of the space adjacent to the electrically conductive member changes, and the oscillating frequency of the oscillator circuit fluctuates in accordance with movements of the object. Therefore, by detecting fluctuations in the oscillating frequency, a moving object can be detected.
An abnormality alarm apparatus in accordance with another aspect of the invention has an alarm device that produces an alarm based on a result of detection by the frequency change detection circuit. For example, the alarm device indicates to a driver that a moving object is detected in the trunk, so that the driver can take a proper action in response to the alarm indication. The alarm may be provided in various forms, such as a sound, a display, etc.
In a load-carrying compartment opening control apparatus in accordance with another aspect of the invention, the at least one electrically conductive member of the moving object detecting apparatus is provided in a load-carrying compartment isolated from a passenger compartment of a vehicle. The load-carrying compartment opening control apparatus has an opener that opens an open-close member of the load-carrying compartment when the frequency change detection circuit detects a moving object during a stop of the vehicle. Therefore, if a human, a pet or the like is unintentionally confined in a trunk, the load-carrying compartment opening control apparatus is able to automatically open the load-carrying compartment.
The frequency change detection circuit may include a receiver that is disposed apart from the antenna and that receives an electromagnetic wave transmitted from the antenna. A change in the frequency of the electromagnetic wave received by the receiver can be detected. Therefore, frequency fluctuations can be detected by the receiver disposed apart from the antenna. Therefore, it is possible for the system of the invention to use the reception equipment of a different system, for example, a smart entry system or the like.